Dissertation > Industrial Technology > Chemical Industry > Other chemical industries > Fermentation industry > Enzyme preparation ( enzyme )

The Optimal Condition of the Enzyme Production from Aspergilllums Niger NL-1,and the Immobilization of the B-Glucosidase by Crosslinked Chitosan

Author SongJingCheng
Tutor ZhaoMingWen
School Nanjing Agricultural College
Keywords An immobilization material NL-1 β- glucosidase Relative activity Immobilized Enzyme Operational stability Crosslinked chitosan Cellulase Carbon Glucose Chitosan microspheres Aspergillus niger Glycoside hydrolase Immobilization method Bran Embedding Crosslinking method The optimum temperature Enzyme activity assay Covalently linked
Type Master's thesis
Year 2012
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β-glucoamylase, also called β-D-glucoside hydrolase, is a kind of cellulases. In nature, the enzyme exists in almost all organisms. Because of their different sources, their natures are different. β-glucoamylase has an important physiological function in the degradation of glycogen of human beings and the carbohydrate metabolism of animals, plants and microorganism. It has an important application in medical, food and biomass conversion. Now cellulose has been widely applied in all kinds of fields, such as medicine, the textile industry, the daily-use chemical industry, paper making, food fermentation industry, industrial laundry, tobacco industry, oil exploitation, treatment of wastewater and animal feed and so on.The paper studied the optimal condition of the enzyme production from Aspergilllums Niger NL-1, and the immobilization of the β-glucosidase by crosslinked chitosan, and the enzymatic characteristics of immobilized and free enzyme. The results show that bran was the best carbon source for β-glycosidase production, and its preferable concentration is4%. Starch, microcrystalline cellulose, glucose, sucrose, cellobiose were are not the carbon sources for β-gLucosidase production.The best incubation time for fermentation was5days, in the case, the highest activity of β-gLucosidase5.88U/mL is obtained. Supplyment with cellobiose as bran carbon source has no induction effect on the enzyme production.The optimal temperature of immobilized and free β-glucosidase was70℃and65℃, respectively, and the optimal pH was4.0and4.5respectively. The activity of immobilized β-glucosidase remained more than75%after stored for11weeks. And the enzyme keep over65%activity after the continuous use of six batches. The results showed that the operating stability, the temperature, and pH range and storage of immobilized β-glucosidase was better than that of free β-glucosidase.

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